This application is related to U.S. patent application Ser. No. 08/904,440, filed on same date herewith, by William C. Y. Lee, et al., and entitled xe2x80x9cCOMPUTER-IMPLEMENTED MICROCELL PREDICTION MODELING WITH TERRAIN ENHANCEMENT,xe2x80x9d which application is incorporated by reference herein.
1. Field of the Invention
The present invention relates to a computer-implemented system for the design and development of cellular telephone systems or other wireless communication systems. In particular, the present invention discloses a modeling system integrated with a comprehensive set of software tools for the design, development and management of cellular telephone systems.
2. Description of Related Art
The capacity of cellular telephone systems in urban areas is typically its most precious commodity. The use of smaller cells, called xe2x80x9cmicrocells,xe2x80x9d has been one of the solutions used to increase the capacity of cellular telephone systems.
Because capacity is such a precious commodity, the design and management decisions made for cellular telephone systems are usually made to maximize the capacity of the system. For example, engineers must design the system to maximize the coverage of the geographic area with the minimum number of cell sites. In addition, interference problems must be studied so that their effect is minimized. Further, the blocking probability of each cell site must be analyzed to ensure proper call initiation.
The design of a cellular telephone system or other wireless communications system is typically performed using modeling techniques before the system is placed in actual usage. The Lee model, described in xe2x80x9cMobile Cellular Telecommunications,xe2x80x9d by William C. Y. Lee, Second Edition, 1995, which is incorporated by reference herein, is the standard model for designing a cellular telephone system. The models and the investigations performed in this area concentrate on analyzing the propagation of electromagnetic waves under a line of sight analysis.
However, calls that are generated from within buildings or that are directed toward cellular phones within buildings are generally not taken into account by system designers. The reflections or blocking of a direct line of sight transmission due to exterior and interior building walls are typically ignored or averaged out during the modeling process. Ignoring or averaging these effects on the transmission of cellular signals was assumed to be proper since cells are small. However, microcell antennas, once placed in operation, need to be adjusted in terms of placement, power output, and antenna beam patterns because the models used do not accurately predict the conditions experienced in actual use of the cellular telephone system.
It can be seen, then, that there is a need for a better modeling tool to more accurately predict conditions present when the cellular telephone system is placed in operation.
To minimize the limitations in the prior art described above, and to minimize other limitations that will become apparent upon reading and understanding th e present specification, the present invention discloses a method, apparatus, and article of manufacture for modeling cellular telephone systems to predict signal strength for cells within buildings under real conditions, by considering the effects of the inter-building and intra-building structures on the transmitted signals.
One object of the present invention i s to solve the above-described problems by using models of the buildings to more accurately predict the conditions that the cellular telephone system will be used under. Another object of the present invention is to increase capacity of the cellular telephone system. It is a further object of the present invention to more accurately model a cellular telephone system. It is a further object of the present invention to reduce the costs of implementing a cellular telephone system.
For a better understanding of the invention, its advantages, and the objects obtained by its use, reference should be made to the drawings which form a further part hereof, and to accompanying descriptive matter, in which there are illustrated and described specific examples of an apparatus in accordance with the invention.